Display Systems With Optical Sensing

ABSTRACT

A head-mounted device may have catadioptric lenses that each include a partial mirror, a quarter wave plate, and a polarizer. An optical system in the head-mounted device may have an infrared light-emitting device and an infrared light-sensing device. The optical system may illuminate a user&#39;s eyes in eye boxes and may gather measurements from the illuminated eye boxes for eye tracking and other functions. The optical system may operate through the catadioptric lenses. To enhance optical system performance, the polarizers may be wire grid polarizers that are formed from conductive lines that exhibit enhanced infrared transmission and/or the quarter wave plates may be formed from cholesteric liquid crystal layers that serve as quarter wave plates at visible wavelengths and that do not serve as quarter wave plates at infrared wavelengths.

This application is a continuation of U.S. patent application Ser. No.17/077,823, filed Oct. 22, 2020, which claims the benefit of provisionalpatent application No. 62/934,143, filed Nov. 12, 2019, which are herebyincorporated by reference herein in their entireties.

FIELD

This relates generally to electronic devices, and, more particularly, toelectronic devices with optical components.

BACKGROUND

Electronic devices sometimes include optical components. For example, awearable electronic device such as a head-mounted device may include adisplay for displaying an image.

Lenses may be used to allow a user of a head-mounted device to focus ona display and view an image. Lenses such as catadioptric lenses may helpreduce lens size and weight, making a head-mounted device comfortable towear. Catadioptric lenses may include optical components such as partialmirrors, wave plates, and polarizers. If care is not taken, there may beincompatibilities between these components and other components in ahead-mounted device. For example, there may be a risk that the opticalcharacteristics of these components will adversely affect the operationof optical sensors.

SUMMARY

An electronic device such as a head-mounted device may have a displaythat displays an image for a user. A user with eyes located in eye boxesmay view the image through lenses that are interposed between the eyeboxes and the display. The lenses may be catadioptric lenses.

A catadioptric lens for a head-mounted device may include a partialmirror, a quarter wave plate, and a polarizer. An optical system in thehead-mounted device may be used for eye tracking and other functions.

The optical system may have an infrared light-emitting device and aninfrared light-sensing device. The optical system may illuminate the eyeboxes and may gather measurements on the illuminated eye boxes duringoperation of the head-mounted device.

The optical system may operate through catadioptric lens structures. Forexample, the light-emitting device may emit infrared illumination thatpasses through a catadioptric lens and corresponding reflected lightfrom the eye boxes may pass through the catadioptric lens to thelight-sensing device.

To enhance optical system performance, the polarizers in thecatadioptric lenses may be may exhibit enhanced infrared transmissionrelative to visible light transmission. At visible light wavelengths,the polarizers serve as linear polarizers. At infrared lightwavelengths, the polarizers are transparent and allow infrared lightassociated with the optical system to pass.

In some configurations, the quarter wave plates of the catadioptriclenses are formed from cholesteric liquid crystal layers that serve asquarter wave plates at visible wavelengths and that do not serve asquarter wave plates at infrared wavelengths. Arrangements may also beused in which light-emitting devices in the optical system are providedwith polarizers that polarize emitted light to enhance transmissionthrough the catadioptric lenses and/or in which light-emitting devicesand/or light-sensing devices are located between the lenses and the eyeboxes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of an illustrative electronic device such as ahead-mounted device in accordance with an embodiment.

FIG. 2 is a top view of a portion of an illustrative head-mounted devicewith a lens in accordance with an embodiment.

FIG. 3 is a graph showing how an optical component in a lens may have anoptical property such as a light transmission parameter that varies as afunction of wavelength in accordance with an embodiment.

FIG. 4 is a top view of an illustrative wire grid polarizer inaccordance with an embodiment.

FIG. 5 is a cross-sectional side view of the wire grid polarizer of FIG.4 in accordance with an embodiment.

FIGS. 6 and 7 are top views of conductive layers that may be patternedinto wires for a wire grid polarizer in accordance with an embodiment.

FIGS. 8, 9, 10, and 11 are side views of illustrative arrangements foroperating an infrared sensor through a lens with optical components inaccordance with an embodiment.

DETAILED DESCRIPTION

Electronic devices may include displays and other components forpresenting content to users. The electronic devices may be wearableelectronic devices. A wearable electronic device such as a head-mounteddevice may have head-mounted support structures that allow thehead-mounted device to be worn on a user's head.

A head-mounted device may contain optical components such as a displayfor displaying visual content and lenses for allowing the user to viewthe visual content on the display. Optical sensors such as infraredsensors may be used to gather information on a user's eyes, facialfeatures, or other body characteristics. This information may be usedfor eye tracking (sometimes referred to as gaze tracking), may be usedfor authentication (e.g., eye biometrics for user identification),facial recognition, and/or other device operations.

During operation, infrared sensors may emit and detect infrared light.This light may pass through the lenses in the head-mounted device. Thelenses may be catadioptric lenses having optical components such aspartial mirrors, wave plates, and polarizers. To help ensurecompatibility between the infrared sensors and the lenses, one or moreof the optical components in the lenses may be formed from material thatis more transparent at infrared wavelengths than at visible wavelengthsor has other wavelength-dependent properties.

A top view of an illustrative head-mounted device is shown in FIG. 1 .As shown in FIG. 1 , head-mounted devices such as electronic device 10may have head-mounted support structures such as housing 12. Housing 12may include portion 12T to allow device 10 to be worn on a user's head.Main housing portion 12M may include optical components 14 (e.g., adisplay, lenses, etc.). Housing structures such as internal supportstructures 121 may support lenses and other optical components 14 (e.g.,structures 121 may serve as lens support structures).

Front face F of housing 12 may face outwardly away from a user's head.Rear face R of housing 12 may face the user. During operation, a user'seyes are placed in eye boxes 18. When the user's eyes are located in eyeboxes 18, the user may view content being displayed by opticalcomponents 14. In some configurations, optical components 14 areconfigured to display computer-generated content that is overlaid overreal-world images (e.g., a user may view the real world throughcomponents 14). In other configurations, which are sometimes describedherein as an example, real-world light is blocked (e.g., by an opaquehousing wall on front face F of housing 12 and/or other portions ofdevice 10).

The support structures of device 10 may include adjustable components.For example, portion 12T of housing 12 may include adjustable straps orother structures that may be adjusted to accommodate different headsizes. Support structures 121 may include motor-driven adjustable lensmounts, manually adjustable lens mounts, and other adjustable opticalcomponent support structures. Structures 121 may be adjusted by a userto adjust the locations of eye boxes 18 to accommodate different userinterpupillary distances. For example, in a first configuration,structures 121 may place lenses and other optical components associatedrespectively with the user's left and right eyes in close proximity toeach other so that eye boxes 18 are separated from each other by a firstdistance and, in a second configuration, structures 121 may be adjustedto place the lenses and other optical components associated with eyeboxes 18 in a position in which eye boxes are separated from each otherby a second distance that is larger than this distance. Lens positionadjustments and other adjustments may be made on information gatheredusing image sensors and other sensors (e.g., information on a user's eyepositions from eye tracking sensors).

In addition to optical components 14, device 10 may contain otherelectrical components 16. Components 14 and/or 16 may include integratedcircuits, discrete components, printed circuits, and other electricalcircuitry. For example, these components may include control circuitryand input-output devices.

The control circuitry of device 10 may include storage and processingcircuitry for controlling the operation of device 10. The controlcircuitry may include storage such as hard disk drive storage,nonvolatile memory (e.g., electrically-programmable-read-only memoryconfigured to form a solid-state drive), volatile memory (e.g., staticor dynamic random-access-memory), etc. Processing circuitry in thecontrol circuitry may be based on one or more microprocessors,microcontrollers, digital signal processors, baseband processors, powermanagement units, audio chips, graphics processing units, applicationspecific integrated circuits, and other integrated circuits. Softwarecode may be stored on storage in the control circuitry and run onprocessing circuitry in the control circuitry to implement controloperations for device 10 (e.g., data gathering operations, operationsinvolving the adjustment of the components of device 10 using controlsignals, etc.). Control circuitry in device 10 may include wired andwireless communications circuitry. For example, the control circuitrymay include radio-frequency transceiver circuitry such as cellulartelephone transceiver circuitry, wireless local area network (WiFi®)transceiver circuitry, millimeter wave transceiver circuitry, and/orother wireless communications circuitry.

Device 10 may be used in a system of multiple electronic devices. Duringoperation, the communications circuitry of device 10 may be used tosupport communication between device 10 and other electronic devices inthe system. For example, one electronic device may transmit video and/oraudio data to device 10 or another electronic device in the system.Electronic devices in the system may use wired and/or wirelesscommunications circuitry to communicate through one or morecommunications networks (e.g., the internet, local area networks, etc.).The communications circuitry may be used to allow data to be received bydevice 10 from external equipment (e.g., a tethered computer, a portabledevice such as a handheld device or laptop computer, online computingequipment such as a remote server or other remote computing equipment,or other electrical equipment) and/or to provide data to externalequipment.

The input-output devices of device 10 (e.g., input-output devices incomponents 16) may be used to allow a user to provide device 10 withuser input. Input-output devices may also be used to gather informationon the environment in which device 10 is operating. Sensors may be usedin gathering eye position information, point-of-gaze information, eyebiometric information (retina features, etc.), other biometricinformation, etc. Output components in the input-output devices mayallow device 10 to provide a user with output and may be used tocommunicate with external electrical equipment.

The input-output devices of device 10 may include one or more displays.In some configurations, a display in device 10 may include left andright display devices (e.g., left and right components such as left andright scanning minor display devices, liquid-crystal-on-silicon displaydevices, digital mirror devices, or other reflective display devices,left and right display panels based on light-emitting diode pixel arrays(e.g., organic light-emitting display panels or display devices based onpixel arrays formed from crystalline semiconductor light-emitting diodedies), liquid crystal display devices panels, and/or or other left andright display devices in alignment with the user's left and right eyes,respectively. In other configurations, the display includes a singledisplay panel that extends across both eyes or uses other arrangementsin which content is provided with a single pixel array.

The display of device 10 is used to display visual content for a user ofdevice 10. The content that is presented on the display may includevirtual objects and other content that is provided to the display bycontrol circuitry 12 and may sometimes be referred to ascomputer-generated content. An image on the display such as an imagewith computer-generated content may be displayed in the absence ofreal-world content or may be combined with real-world content. In someconfigurations, a real-world image may be captured by a camera (e.g., aforward-facing camera) so that computer-generated content may beelectronically overlaid on portions of the real-world image (e.g., whendevice 10 is a pair of virtual reality goggles with an opaque display).

The input-output circuitry of device 10 may include sensors. The sensorsmay include, for example, three-dimensional sensors (e.g.,three-dimensional image sensors such as structured light sensors thatemit beams of light and that use two-dimensional digital image sensorsto gather image data for three-dimensional images from light spots thatare produced when a target is illuminated by the beams of light,binocular three-dimensional image sensors that gather three-dimensionalimages using two or more cameras in a binocular imaging arrangement,three-dimensional lidar (light detection and ranging) sensors,three-dimensional radio-frequency sensors, or other sensors that gatherthree-dimensional image data), cameras (e.g., infrared and/or visibledigital image sensors), gaze tracking sensors (e.g., a gaze trackingsystem based on an image sensor and, if desired, a light source thatemits one or more beams of light that are tracked using the image sensorafter reflecting from a user's eyes), touch sensors, buttons, capacitiveproximity sensors, light-based (optical) proximity sensors, otherproximity sensors, force sensors, sensors such as contact sensors basedon switches, gas sensors, pressure sensors, moisture sensors, magneticsensors, audio sensors (microphones), ambient light sensors, lightsensors that make user measurements, microphones for gathering voicecommands and other audio input, sensors that are configured to gatherinformation on motion, position, and/or orientation (e.g.,accelerometers, gyroscopes, compasses, and/or inertial measurement unitsthat include all of these sensors or a subset of one or two of thesesensors), and/or other sensors.

User input and other information may be gathered using sensors and otherinput devices in the input-output devices of device 10. If desired,device 10 may include haptic output devices (e.g., vibratingcomponents), light-emitting diodes and other light sources, speakerssuch as ear speakers for producing audio output, and other electricalcomponents used for input and output. If desired, device 10 may includecircuits for receiving wireless power, circuits for transmitting powerwirelessly to other devices, batteries and other energy storage devices(e.g., capacitors), joysticks, buttons, and/or other components.

Some or all of housing 12 may serve as support structures (see, e.g.,housing portion 12T). In configurations in which electronic device 10 isa head-mounted device (e.g., a pair of glasses, goggles, a helmet, ahat, etc.), portion 12T and/or other portions of housing 12 may serve ashead-mounted support structures (e.g., structures forming a helmethousing, head straps, temples in a pair of eyeglasses, goggle housingstructures, and/or other head-mounted structures). The head-mountedsupport structures may be configured to be worn on a head of a userduring operation of device 10 and may support display(s), lenses,sensors, other input-output devices, control circuitry, and/or othercomponents.

FIG. 2 is a top view of a portion of electronic device 10 in anillustrative configuration in which electronic device 10 is ahead-mounted device. As shown in FIG. 2 , electronic device 10 mayinclude display 14A. Display 14A may have an array of pixels P fordisplaying images for a user. A user with eyes located in a pair of eyeboxes such as eye box 18 may view images on display 14A through a pairof lenses such as lens 14B. A single lens 14B and eye box 18 are shownin FIG. 2 . Display 14A may include left and right display portions(sometimes referred to as left and right displays, left and rightdisplay devices, left and right display components, or left and rightpixel arrays).

Optical sensing system 36 may have one or more components that emitlight 40 such as light-emitting device 38 and one or more componentsthat detect light 42 such as light-sensing device 44. Optical sensingsystem 36 may operate at visible light wavelengths, infrared lightwavelengths, and/or ultraviolet light wavelengths. In an illustrativeconfiguration, which may sometimes be described herein as an example,optical sensing system 36 operates at infrared wavelengths. Opticalsensing system 36 may therefore sometimes be referred to as an infraredsensing system or infrared sensor. Device 38 may be based on one or morelight-emitting components such as light-emitting diodes and/or lasersand may operate at one or more wavelengths. As an example, device 38 maybe an infrared light-emitting diode and/or infrared laser diode or mayhave a set of infrared light-emitting diodes and/or infrared laserdiodes. Device 44 may be a light detecting component such as asingle-element infrared photodetector, a set of multiple infraredphotodetectors, a two-dimensional infrared image sensor, and/or otherlight-sensing components.

Optical sensing system 36 may operate through lens 14B. For example,when a user's eyes are located in eye boxes 18, sensor system 36 maygather information on the user's eyes. This information may be used tosupport authentication operations (eye biometrics), identificationoperations (e.g., discriminating between multiple users of device 10),eye position sensing, eye tracking (gaze tracking) operations in whichthe user's point-of-gaze (direction of view) is monitored, facialrecognition operations, or other operations of device 10.

Lens 14B may be a catadioptric lens. During operation, light rayspassing from display 14A to eye box 18 follow a folded path through lens14B. This helps allow the size and weight of lens 14B to be reduced. Inthe example of FIG. 2 , lens 14B has partial minor (e.g., a half mirroror other minor with a light transmission of 10-90%, 20-80%, 30-70%, orother suitable light transmission value and a light reflection of90-10%, 80-20%, 70-30%, or other suitable light reflection value), awave plate such as quarter wave plate 30, and reflective polarizer 34(e.g., a linear polarizer that passes light that is polarized along theY axis and that reflects light that is polarized along the X axis).Mirror 26 may be formed on the outwardly facing surface of transparentlens element 28. This outwardly facing lens element surface may beaspherically convex (as an example). Quarter wave plate 30 may be formedbetween a cylindrically concave inwardly facing surface of lens element28 and a corresponding cylindrically convex outwardly facing surface oflens element 32 (e.g., using adhesive bonding that attaches lens element28 to lens element 32). Reflective polarizer 34 may be formed on anaspherically concave inwardly facing surface of lens element 32. Asshown in FIG. 2 , polarizer 34 faces eye box 18 and minor 26 facesdisplay 14A.

In an illustrative arrangement, lens 14B receives circularly polarizedimage light from display 14A. Display 14A may have an associatedcircular polarizer such as circular polarizer Linear polarizer 24 ofpolarizer 20 may receive unpolarized image light from pixels P and mayallow linearly polarized light to pass to quarter wave plate 22. Quarterwave plate 22 of circular polarizer 20 may convert linearly polarizedlight from linear polarizer 24 to circularly polarized light (e.g.,right-hand circularly polarized light). In this way, light from display14A passes to lens 14B as circularly polarized light. Reflections ofthis light from mirror 26 are suppressed by polarizer 20.

Sensor system 38 and/or the optical components that make up lens 14B maybe configure to allow sensor system 38 to operate through lens 14B. Forexample, one or more of the layers of lens 14B such as the layersforming mirror 26, wave plate 30, and/or polarizer 34 may be configuredto have different optical characteristics at visible and infraredwavelengths. This allows lens 14B to pass visible light images fromdisplay 14A to eye box 18 while allowing infrared light for system 36 topass from system 36 through lens 14B to a user's eye in eye box 18 andto subsequently pass from the user's eye in eye box 18 to system 36.

In an illustrative configuration, polarizer 34 may be configured to betransparent at infrared wavelengths (e.g., at a wavelength of 810 nmand/or other near infrared wavelengths). When light is linearly alignedalong the pass axis of polarizer 34, polarizer 34 may exhibit a lighttransmission value of 100% or nearly 100% for visible light and infraredlight. When light is linearly polarized orthogonally to the pass axis,visible light will be blocked and infrared light will be transmitted. Asshown by curve 46 of the graph of FIG. 3 , for example, polarizer 34may, for light that is polarized orthogonal to the pass axis ofpolarizer 34, exhibit a visible light transmission value T (e.g., at avisible light wavelength of 500 nm or other suitable visible lightwavelength) that is less than 50%, less than 30%, less than 20%, lessthan 10%, or other suitable fraction of its infrared light transmissionvalue (e.g. at an infrared wavelength of 810 nm or other suitableinfrared wavelengths). By exhibiting more infrared light transmissionthan visible light transmission, the amount that infrared lightassociated with system 36 (e.g., emitted light 40 and/or sensed light42) is attenuated by passing through lens 14B may be reduced. Ifdesired, other optical characteristics of the optical components indevice 10 may be configured to be different between infrared and visiblewavelengths. For example, other component(s) may have characteristicsthat differ by at least 40%, at least 50%, at least 80%, or othersuitable amount between visible and infrared wavelengths (e.g., waveplate 30 may be effective as a quarter wave plate only at visible lightwavelengths and not at infrared light wavelengths). Arrangements inwhich the infrared light transmission of polarizer 34 is enhancedrelative to the visible light transmission of polarizer 34 may sometimesbe described herein as an example.

A portion of an illustrative reflective polarizer such as polarizer 34is shown in FIG. 4 . In the example of FIG. 4 , polarizer 34 is a wiregrid polarizer (sometimes referred to as a wire grid film polarizer)having a series of parallel conductive lines 48. Lines 48 (which maysometimes be referred to as elongated strips) may be formed from aconductive material separated by respective gaps G. Lines 48 of FIG. 4run parallel to each other along the X axis. In this type ofarrangement, polarizer 34 will pass light that is linearly polarizedalong the Y axis (the pass axis of polarizer 34 is along the Y axis) andwill reflect light (and thereby block light) that is linearly polarizedalong the X axis.

Lines 48 may be characterized by a width W of 50 nm, at least 15 nm, atleast 30 nm, less than 200 nm, less than 100 nm, or other suitable widthand a pitch PT of about 90-100 nm, at least 30 nm, at least 45 nm, lessthan 180 nm, less than 120 nm, or other suitable pitch. The thickness oflines 48 in dimension Z may be about 30 nm, at least 3 nm, at least 6nm, at least 15 nm, less than 300 nm, less than 150 nm, less than 70 nm,10-90 nm, and/or other suitable thickness. Lines 48 may be deposited ona dielectric substrate such as substrate 50 and may be pattered byetching, lift-off, shadow masking, printing, and/or other patterningtechniques suitable for patterning a conductive thin-film layer. Across-sectional side view of polarizer 34 of FIG. 4 taken along line 47and viewed in direction 49 is shown in FIG. 5 . Substrate 50 may be apolymer film (e.g., optical polycarbonate or other transparent polymer)or an inorganic polymer material. The thickness of substrate 50 may beabout 1-9 microns, 3 microns, at least 0.2 microns, at least 0.7microns, at least 1.5 microns, less than 6 microns, less than 4 microns,or other suitable thickness. Optional coatings (e.g., to preventdegradation of lines 48, etc.) may be formed on polarizer 34. Ifdesired, the structures of polarizer 34 and/or other optical layers inlens 14B may be formed as coatings on lens elements such as lenselements 32 and/or 28. Arrangements in which polarizer 34 and otheroptical layers are formed as stand-alone films that are attached to lenselements 32 and/or 28 using adhesive may sometimes be described hereinas an example.

To enhance infrared light transmission of lines 48 relative to visiblelight, lines 48 may be formed from a material with enhanced infraredlight transmission relative to visible light. This material may be ananomaterial formed from a mixture of two or more materials havingfeature sizes of about 1-1000 nm, at least 10 nm, at least 100 nm, lessthan 500 nm, less than 200 nm, or other suitable size. The nanomaterialmay have subwavelength features that form a photonic crystal (as anexample).

With an illustrative configuration, the material of lines 48 contain amixture of a first material with a second material. The first materialmay form islands within a film formed of the second material asillustrated by the islands of first material 52 that are formed withinthe layer of second material 54 in the illustrative discontinuousmaterial of lines 48 of FIG. 6 or the first material may form continuousfilaments of material within the second material as illustrated byirregular strands (continuous filaments) of first material 52 within theirregular strands (continuous filaments) of second material 54 in thematerial of lines 48 of FIG. 7 . In an illustrative arrangement, thefirst material is a metal (e.g., aluminum) and the second material is asemiconductor (e.g., silicon or germanium). The patterned Al—Simaterials of FIGS. 6 and 7 may be formed by co-sputtering the first andsecond materials (and, if desired, low-temperature annealing thesematerials under vacuum).

The structures of FIGS. 6 and 7 (e.g., the first regions of the firstmaterial and the second regions of the second material) may havesubwavelength feature sizes (e.g., widths less than 300 nm, less than150 nm, less than 75 nm, less than 30 nm, or other suitable size). Inthe arrangement of FIG. 7 , a distinct phase separation is createdduring processing (e.g., spinodal decomposition) to create a spinodalpattern.

Silicon and germanium are opaque at visible wavelengths and transparentat infrared wavelengths. The incorporation of semiconductors such assilicon and/or germanium into polarizer 34 may help allow polarizer 34to operate as a reflective polarizer at visible light wavelengths and asa transparent (non-polarizing) layer at infrared wavelengths. Othermaterials (e.g., other non-metals such as other semiconductors and/orother dielectrics, etc.) may also be used to help enhance infrared lighttransmission relative to visible light transmission.

The infrared transmission of silicon is greater than the infraredtransmission of germanium, so incorporation of silicon into the materialof lines 48 may enhance infrared light transmission (e.g., at 810 nm).The infrared transmission of germanium cuts off at about 600 nm, whereassilicon may be transparent at shorter wavelengths (e.g., silicon mayexhibit a cutoff wavelength of 350 nm). As a result, the incorporationof germanium into the material of layer 48 instead of silicon may helpenhance the ratio of light transmission at a desired infrared wavelengthassociated with operation of system 36 (e.g., a wavelength of 810 nm forlight 40 and 42 of FIG. 2 , as an example) to light transmission at agiven visible light wavelength (e.g., 500 nm, as an example). Othersemiconductors, dielectric materials, and/or metals may be incorporatedinto the material forming lines 48 of polarizer 34 to enhance infraredlight transmission relative to visible light transmission, if desired.

By using a two-part material such as an aluminum-silicon mixture withseparate regions of aluminum and silicon or other material for lines 48that exhibits enhanced infrared light transmission (e.g., relative tovisible light transmission and/or relative to the infrared lighttransmission that would be present if lines 48 were formed from purealuminum or other metal), the transmission of light 40 and 42 throughlens 14B may be enhanced and the performance of optical system 36 may beenhanced.

When polarizer 34 has enhanced infrared light transmission, thetransmission of emitted light 40 through polarizer 34 and thetransmission of counterpropagating light 42 that has reflected off of auser's eye in eye box 18 is enhanced, particularly when the polarizationstate of light 40 and/or 42 is orthogonal to the pass axis of polarizer34 upon passing through polarizer 34. Because infrared lighttransmission is enhanced and the light-blocking properties of polarizer34 are reduced for infrared light, system 36 may, if desired, useunpolarized light-emitting and light-sensing components (e.g., component38 may emit unpolarized infrared light and/or component 44 may detectunpolarized infrared light).

In addition to or instead of enhancing the infrared light transmissionof polarizer 34 (e.g., by forming lines 48 from an aluminum-siliconmaterial or other material with enhanced infrared transmission), theperformance of sensor system 36 can be enhanced by controlling thepolarization state of light 40 and 42 as light 40 and 42 passes throughlens 14B (e.g., so that light 40 and 42 are linearly polarized inalignment with the pass axis of polarizer 34).

Consider, as an example, the arrangement of FIG. 8 in which device 38has been provided with a circular polarizer so that emitted light 40from device 38 has circular polarization. As shown in FIG. 8 ,light-emitting device 38 may be configured to emit light 40 that isright-hand circularly polarized (RCP). Device 38 of FIG. 8 may have apolarizer such as circular polarizer 60. Circular polarizer 60 may havelinear polarizer 62 and quarter wave plate 64. Linear polarizer 62 ofcircular polarizer 60 may be interposed between quarter wave plate 64and device 38. Light 40 that is emitted by device 38 may initially belinearly polarized or may become linearly polarized upon passing throughlinear polarizer 62. After passing through quarter wave plate 64, light40 of FIG. 8 has right hand circular polarization. Mirror 26 ispartially reflective and partially transparent to visible light and toinfrared light 40 (e.g., the transmission of mirror 26 is at least 10%,at least 40%, less than 90%, less than 60%, etc.). Light remainsright-hand circularly polarized after passing through mirror 26. Quarterwave plate converts circularly polarized light to linearly polarizedlight. Linearly polarized light 40 exiting quarter wave plate 30 isaligned with the pass axis of polarizer 34 and illuminates a user's eyein eye box 18, thereby producing counterpropagating light 42 that ischaracterized by linear polarization aligned with the pass axis ofpolarizer 34. After passing through quarter wave plate light 42 becomesleft-hand circularly polarized and this polarization state is preservedas light 42 passes through mirror 26. Light-sensing device 44 of FIG. 8may be polarization insensitive and may therefore can sense light 42. Asthis example demonstrates, polarizer 34 need not be provided withinfrared-transparent lines 48 in arrangements in which infrared light 40and 42 is linearly polarized along the pass axis of polarizer 34 whenpassing through polarizer 34.

Another illustrative arrangement is shown in FIG. 9 . In theillustrative configuration of FIG. 9 , quarter wave plate 30 does notserve as a quarter wave plate at infrared wavelengths and is transparentto infrared light. Light-emitting device 38 may have a polarizer such alinear polarizer 62 and/or may otherwise be configured to emit infraredlight 40 that is linearly polarized. Mirror 26 is partially transparentand transmits light 40 without changing the polarization of light 40.Quarter wave plate 30 may be formed from a cholesteric liquid crystalfilm or other material that is transparent to infrared light and thatdoes not serve as a quarter wave plate at infrared wavelengths and thatforms a quarter wave plate at visible light wavelengths. At visiblelight wavelengths, quarter wave plate 30 converts the polarization oflight passing through quarter wave plate 30. Because quarter wave plate30 is only effective at visible light wavelengths, however, linearlypolarized infrared light 40 that is received from mirror 26 passesthrough plate 30 without any change to its polarization state. Thisinfrared light remains linearly polarized in alignment with the passaxis of linear polarizer 40. Reflected infrared light 42 is alsolinearly polarized in alignment with the pass axis of linear polarizer40. Reflected infrared light 42 passes through plate 30 without changeto its polarization state. Linearly polarized infrared light 42 fromplate 30 then passes through mirror 26 and is received as linearlypolarized light by light-sensing device 44, which may be insensitive topolarization.

Two additional illustrative configurations for device 10 are shown inFIGS. 10 and 11 .

In the example of FIG. 10 , light-emitting device 38 is located betweenpolarizer 34 and eye box 18, so light 40 does not pass through lens 14B.Light 40 may have a linear polarization that is aligned with the passaxis of polarizer 34 (e.g., device 36 may have a linear polarizer or mayotherwise be configured to emit linearly polarized light). Reflectedlight 42 will be linearly polarized in alignment with this pass axiswhen passing from eye box 18 through polarizer 34 to quarter wave plate30. Quarter wave plate 30 may convert the linear polarization of thislight 42 to circular polarization. Circularly polarized light 32 fromplate 30 will pass through mirror 26 without changing its polarizationstate. Device 44 may be insensitive to the polarization state ofincoming light and can therefore sense circularly polarized light 42passing through mirror 26.

In the example of FIG. 11 , light-sensing device 44 is located betweenlens 14B and eye box 18, whereas lens 14B is located betweenlight-emitting device 38 and eye box 18. Light-emitting device 38 emitsinfrared light 40 that passes through minor 26 without changing itspolarization state.

In a first configuration of device 10 of FIG. 11 , quarter wave plate 30is transparent to infrared light and does not change the polarization oflight 40. In this first configuration, device 38 emits light 40 that islinearly polarized, so that light 40 that reaches polarizer 34 islinearly polarized in alignment with the pass axis of polarizer 34.Reflected light from eye box 18 reaches light-sensing device 44 withoutpassing through lens 14B. Light-sensing device 44 may be insensitive tothe polarization state of received light and can therefore sense light42.

In a second configuration of device 10 of FIG. 11 , quarter wave plate30 serves as a quarter wave plate for infrared light. Device 38 has acircular polarizer so that emitted light 40 from device 38 is circularlypolarized when passing through minor 26 and becomes linearly polarizedin alignment with the pass axis of polarizer 34 when passing throughquarter wave plate 30. Reflected light (e.g., infrared light 42) reacheslight-sensing device 44 without passing through lens 14B. Light-sensingdevice 44 may be insensitive to the polarization state of received lightand can therefore sense light 42.

Regardless of the configuration used for device 10 (see, e.g., thearrangements of FIGS. 2, 8, 9, 10 , and/or 11), infrared transparentstructures may be incorporated into mirror 26 and/or into polarizer 34to help enhance infrared light transmission and thereby enhance theperformance of sensor system 36. For example, polarizer 34 may includelines patterned from a thin film having first regions of first materialand second regions of a second material where the first regions arediscontinuous islands surrounded by the second material or where thatthe first and second regions form continuous filaments, minor 26 may beformed from a thin film having first regions of first material andsecond regions of a second material where the first regions arediscontinuous islands surrounded by the second material or where thatthe first and second regions form continuous filaments, and/or polarizer34, minor 26, or other lens structures may be formed from otherstructures that have an enhanced infrared transmission relative tovisible light transmission.

As described above, one aspect of the present technology is thegathering and use of information such as sensor information. The presentdisclosure contemplates that in some instances, data may be gatheredthat includes personal information data that uniquely identifies or canbe used to contact or locate a specific person. Such personalinformation data can include demographic data, location-based data,telephone numbers, email addresses, twitter ID's, home addresses, dataor records relating to a user's health or level of fitness (e.g., vitalsigns measurements, medication information, exercise information), dateof birth, username, password, biometric information, or any otheridentifying or personal information.

The present disclosure recognizes that the use of such personalinformation, in the present technology, can be used to the benefit ofusers. For example, the personal information data can be used to delivertargeted content that is of greater interest to the user. Accordingly,use of such personal information data enables users to calculatedcontrol of the delivered content. Further, other uses for personalinformation data that benefit the user are also contemplated by thepresent disclosure. For instance, health and fitness data may be used toprovide insights into a user's general wellness, or may be used aspositive feedback to individuals using technology to pursue wellnessgoals.

The present disclosure contemplates that the entities responsible forthe collection, analysis, disclosure, transfer, storage, or other use ofsuch personal information data will comply with well-established privacypolicies and/or privacy practices. In particular, such entities shouldimplement and consistently use privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining personal information data private andsecure. Such policies should be easily accessible by users, and shouldbe updated as the collection and/or use of data changes. Personalinformation from users should be collected for legitimate and reasonableuses of the entity and not shared or sold outside of those legitimateuses. Further, such collection/sharing should occur after receiving theinformed consent of the users. Additionally, such entities shouldconsider taking any needed steps for safeguarding and securing access tosuch personal information data and ensuring that others with access tothe personal information data adhere to their privacy policies andprocedures. Further, such entities can subject themselves to evaluationby third parties to certify their adherence to widely accepted privacypolicies and practices. In addition, policies and practices should beadapted for the particular types of personal information data beingcollected and/or accessed and adapted to applicable laws and standards,including jurisdiction-specific considerations. For instance, in theUnited States, collection of or access to certain health data may begoverned by federal and/or state laws, such as the Health InsurancePortability and Accountability Act (HIPAA), whereas health data in othercountries may be subject to other regulations and policies and should behandled accordingly. Hence different privacy practices should bemaintained for different personal data types in each country.

Despite the foregoing, the present disclosure also contemplatesembodiments in which users selectively block the use of, or access to,personal information data. That is, the present disclosure contemplatesthat hardware and/or software elements can be provided to prevent orblock access to such personal information data. For example, the presenttechnology can be configured to allow users to select to “opt in” or“opt out” of participation in the collection of personal informationdata during registration for services or anytime thereafter. In anotherexample, users can select not to provide certain types of user data. Inyet another example, users can select to limit the length of timeuser-specific data is maintained. In addition to providing “opt in” and“opt out” options, the present disclosure contemplates providingnotifications relating to the access or use of personal information. Forinstance, a user may be notified upon downloading an application (“app”)that their personal information data will be accessed and then remindedagain just before personal information data is accessed by the app.

Moreover, it is the intent of the present disclosure that personalinformation data should be managed and handled in a way to minimizerisks of unintentional or unauthorized access or use. Risk can beminimized by limiting the collection of data and deleting data once itis no longer needed. In addition, and when applicable, including incertain health related applications, data de-identification can be usedto protect a user's privacy. De-identification may be facilitated, whenappropriate, by removing specific identifiers (e.g., date of birth,etc.), controlling the amount or specificity of data stored (e.g.,collecting location data at a city level rather than at an addresslevel), controlling how data is stored (e.g., aggregating data acrossusers), and/or other methods.

Therefore, although the present disclosure broadly covers use ofinformation that may include personal information data to implement oneor more various disclosed embodiments, the present disclosure alsocontemplates that the various embodiments can also be implementedwithout the need for accessing personal information data. That is, thevarious embodiments of the present technology are not renderedinoperable due to the lack of all or a portion of such personalinformation data.

Physical environment: A physical environment refers to a physical worldthat people can sense and/or interact with without aid of electronicsystems. Physical environments, such as a physical park, includephysical articles, such as physical trees, physical buildings, andphysical people. People can directly sense and/or interact with thephysical environment, such as through sight, touch, hearing, taste, andsmell.

Computer-generated reality: in contrast, a computer-generated reality(CGR) environment refers to a wholly or partially simulated environmentthat people sense and/or interact with via an electronic system. In CGR,a subset of a person's physical motions, or representations thereof, aretracked, and, in response, one or more characteristics of one or morevirtual objects simulated in the CGR environment are adjusted in amanner that comports with at least one law of physics. For example, aCGR system may detect a person's head turning and, in response, adjustgraphical content and an acoustic field presented to the person in amanner similar to how such views and sounds would change in a physicalenvironment. In some situations (e.g., for accessibility reasons),adjustments to characteristic(s) of virtual object(s) in a CGRenvironment may be made in response to representations of physicalmotions (e.g., vocal commands). A person may sense and/or interact witha CGR object using any one of their senses, including sight, sound,touch, taste, and smell. For example, a person may sense and/or interactwith audio objects that create 3D or spatial audio environment thatprovides the perception of point audio sources in 3D space. In anotherexample, audio objects may enable audio transparency, which selectivelyincorporates ambient sounds from the physical environment with orwithout computer-generated audio. In some CGR environments, a person maysense and/or interact only with audio objects. Examples of CGR includevirtual reality and mixed reality.

Virtual reality: A virtual reality (VR) environment refers to asimulated environment that is designed to be based entirely oncomputer-generated sensory inputs for one or more senses. A VRenvironment comprises a plurality of virtual objects with which a personmay sense and/or interact. For example, computer-generated imagery oftrees, buildings, and avatars representing people are examples ofvirtual objects. A person may sense and/or interact with virtual objectsin the VR environment through a simulation of the person's presencewithin the computer-generated environment, and/or through a simulationof a subset of the person's physical movements within thecomputer-generated environment.

Mixed reality: In contrast to a VR environment, which is designed to bebased entirely on computer-generated sensory inputs, a mixed reality(MR) environment refers to a simulated environment that is designed toincorporate sensory inputs from the physical environment, or arepresentation thereof, in addition to including computer-generatedsensory inputs (e.g., virtual objects). On a virtuality continuum, amixed reality environment is anywhere between, but not including, awholly physical environment at one end and virtual reality environmentat the other end. In some MR environments, computer-generated sensoryinputs may respond to changes in sensory inputs from the physicalenvironment. Also, some electronic systems for presenting an MRenvironment may track location and/or orientation with respect to thephysical environment to enable virtual objects to interact with realobjects (that is, physical articles from the physical environment orrepresentations thereof). For example, a system may account formovements so that a virtual tree appears stationery with respect to thephysical ground. Examples of mixed realities include augmented realityand augmented virtuality. Augmented reality: an augmented reality (AR)environment refers to a simulated environment in which one or morevirtual objects are superimposed over a physical environment, or arepresentation thereof. For example, an electronic system for presentingan AR environment may have a transparent or translucent display throughwhich a person may directly view the physical environment. The systemmay be configured to present virtual objects on the transparent ortranslucent display, so that a person, using the system, perceives thevirtual objects superimposed over the physical environment.Alternatively, a system may have an opaque display and one or moreimaging sensors that capture images or video of the physicalenvironment, which are representations of the physical environment. Thesystem composites the images or video with virtual objects, and presentsthe composition on the opaque display. A person, using the system,indirectly views the physical environment by way of the images or videoof the physical environment, and perceives the virtual objectssuperimposed over the physical environment. As used herein, a video ofthe physical environment shown on an opaque display is called“pass-through video,” meaning a system uses one or more image sensor(s)to capture images of the physical environment, and uses those images inpresenting the AR environment on the opaque display. Furtheralternatively, a system may have a projection system that projectsvirtual objects into the physical environment, for example, as ahologram or on a physical surface, so that a person, using the system,perceives the virtual objects superimposed over the physicalenvironment. An augmented reality environment also refers to a simulatedenvironment in which a representation of a physical environment istransformed by computer-generated sensory information. For example, inproviding pass-through video, a system may transform one or more sensorimages to impose a select perspective (e.g., viewpoint) different thanthe perspective captured by the imaging sensors. As another example, arepresentation of a physical environment may be transformed bygraphically modifying (e.g., enlarging) portions thereof, such that themodified portion may be representative but not photorealistic versionsof the originally captured images. As a further example, arepresentation of a physical environment may be transformed bygraphically eliminating or obfuscating portions thereof. Augmentedvirtuality: an augmented virtuality (AV) environment refers to asimulated environment in which a virtual or computer generatedenvironment incorporates one or more sensory inputs from the physicalenvironment. The sensory inputs may be representations of one or morecharacteristics of the physical environment. For example, an AV park mayhave virtual trees and virtual buildings, but people with facesphotorealistically reproduced from images taken of physical people. Asanother example, a virtual object may adopt a shape or color of aphysical article imaged by one or more imaging sensors. As a furtherexample, a virtual object may adopt shadows consistent with the positionof the sun in the physical environment.

Hardware: there are many different types of electronic systems thatenable a person to sense and/or interact with various CGR environments.Examples include head mounted systems, projection-based systems,heads-up displays (HUDs), vehicle windshields having integrated displaycapability, windows having integrated display capability, displaysformed as lenses designed to be placed on a person's eyes (e.g., similarto contact lenses), headphones/earphones, speaker arrays, input systems(e.g., wearable or handheld controllers with or without hapticfeedback), smartphones, tablets, and desktop/laptop computers. A headmounted system may have one or more speaker(s) and an integrated opaquedisplay. Alternatively, a head mounted system may be configured toaccept an external opaque display (e.g., a smartphone). The head mountedsystem may incorporate one or more imaging sensors to capture images orvideo of the physical environment, and/or one or more microphones tocapture audio of the physical environment. Rather than an opaquedisplay, a head mounted system may have a transparent or translucentdisplay. The transparent or translucent display may have a mediumthrough which light representative of images is directed to a person'seyes. The display may utilize digital light projection, OLEDs, LEDs,uLEDs, liquid crystal on silicon, laser scanning light source, or anycombination of these technologies. The medium may be an opticalwaveguide, a hologram medium, an optical combiner, an optical reflector,or any combination thereof. In one embodiment, the transparent ortranslucent display may be configured to become opaque selectively.Projection-based systems may employ retinal projection technology thatprojects graphical images onto a person's retina. Projection systemsalso may be configured to project virtual objects into the physicalenvironment, for example, as a hologram or on a physical surface.

The foregoing is merely illustrative and various modifications can bemade to the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. A head-mounted device, comprising: a lens thatincludes a wire grid polarizer that exhibits more infrared lighttransmission than visible light transmission; an infrared light-emittingdevice configured to emit infrared light through the lens; and aninfrared light-sensing device configured to detect infrared lightthrough the lens.
 2. The head-mounted device of claim 1, wherein thelens comprises a catadioptric lens.
 3. The head-mounted device of claim1, wherein the wire grid polarizer is formed from parallel lines, andeach of the parallel lines comprises first regions of a first materialand second regions of a second material that is different from the firstmaterial.
 4. The head-mounted device of claim 3, wherein the firstmaterial comprises a metal.
 5. The head-mounted device of claim 4,wherein the second material comprises a non-metal.
 6. The head-mounteddevice of claim 3, wherein the first regions form islands within thesecond regions.
 7. The head-mounted device of claim 3, wherein the firstregions are continuous regions and wherein the second regions arecontinuous regions.
 8. The head-mounted device of claim 1, furthercomprising: a display visible through the lens from an eye box.
 9. Thehead-mounted device of claim 8, the infrared light-emitting device isbetween the wire grid polarizer and the eye box.
 10. The head-mounteddevice of claim 1, wherein the lens comprises a layer that forms avisible-light quarter wave plate that is transparent at infraredwavelengths and does not form a quarter wave plate at infraredwavelengths.
 11. The head-mounted device of claim 1, wherein the layercomprises a cholesteric liquid crystal layer.
 12. A head-mounted device,comprising: a lens that includes a layer that serves as a quarter waveplate at visible light wavelengths and that does not serve as a quarterwave plate at infrared wavelengths; a light-emitting device configuredto emit infrared light through the lens; and an infrared image sensorconfigured to detect infrared light that has passed through the lens.13. The head-mounted device of claim 12, wherein the lens furtherincludes a polarizer and a partial minor.
 14. The head-mounted device ofclaim 12, wherein the layer comprises a cholesteric liquid crystallayer.
 15. The head-mounted device of claim 12, wherein the lens furtherincludes a wire grid polarizer that exhibits more infrared lighttransmission than visible light transmission.
 16. The head-mounteddevice of claim 15, wherein the wire grid polarizer comprises parallellines, and each of the parallel lines includes first regions of a firstmaterial and second regions of a second material.
 17. An electronicdevice, comprising: a transparent structure that includes a polarizerconfigured exhibit a first transmission at infrared light wavelengthsand a second transmission at visible light wavelengths that is less thanthe first transmission; an infrared light-emitting device configured toemit infrared light through the transparent structure; and an infraredlight-sensing device configured to detect infrared light through thetransparent structure.
 18. The electronic device of claim 17, whereinthe transparent structure is a catadioptric lens.
 19. The electronicdevice of claim 17, wherein the polarizer is formed from parallel lines,and each of the parallel lines comprises first regions of a firstmaterial and second regions of a second material that is different fromthe first material.
 20. The electronic device of claim 17, wherein thetransparent structure comprises a layer that forms a quarter wave plateat the visible light wavelengths and does not form a quarter wave plateat the infrared light wavelengths.